#103116  by tigerstrat
 Thu Sep 08, 2011 8:05 pm
Jerry1996x wrote:Question. Im getting a Twin reverb, and hopefully a hard truckers 2x12. Im pretty sure twins handle up to 4 ohms. I guess that means i have to have the cab wired parallel, correct me if im wrong. Also, how will this effect the loudness of the cab?
wiring depends on the ohm rating of the speakers it will be loaded with.
 #103119  by hippieguy1954
 Fri Sep 09, 2011 2:47 am
tigerstrat wrote:
Jerry1996x wrote:Question. Im getting a Twin reverb, and hopefully a hard truckers 2x12. Im pretty sure twins handle up to 4 ohms. I guess that means i have to have the cab wired parallel, correct me if im wrong. Also, how will this effect the loudness of the cab?
wiring depends on the ohm rating of the speakers it will be loaded with.
Twins work best and are factory wired with two 8ohm speakers wired in parallel for 4 ohms. The 4 ohm load will give you the best results. The lower the ohms, the more watts!
:smile: :smile: :smile:
 #103154  by tigerstrat
 Fri Sep 09, 2011 11:29 pm
mkaufman wrote:My Twin head (Showman Reverb) has a speaker and external speaker jack. What happens to the ohms if both jacks are used?
parallel jacks: in order to have a correct 4 ohm load on the amp, you could use one jack with one 4 ohm cab, or you could have each jack going to a separate 8 ohm load (which in turn could consist of a single 8 ohm speaker, or two 16 ohm speakers wired in parallel, or two 4 ohm speakers wired in series...)... also if you are using two 8 ohm cabs and one of them has a 2 parallel jacks, you can daisy chain them one to the next out just a single amp jack and still have the correct 4 ohm load.

in other words, the speakers that you connect to the amp and how they are wired, not the jacks, are what determine the ohms that your amp "sees", as they say.
 #103156  by hippieguy1954
 Sat Sep 10, 2011 5:22 am
The extention speaker jack on a Twin is also 4ohms, so you can use an extention speaker cab with two 8 ohm speakers for the 4ohms. :smile: :smile: :smile:
 #103163  by hippieguy1954
 Sat Sep 10, 2011 8:18 am
mkaufman wrote:So I can run (2) 2x12's, each with (2) 8-ohm speakers wired in parallel.

Sound easy!

Just need someone to carry my cabs!

mk
Yes! Exactly! It is very easy,and when you find someone to carry your cabs, let me know so they can carry mine too! Actually you might find out you only want/need one cab most times, but that is personal preference. I use a very well padded and cushioned hand truck with bungi cords unless I have help lol.
:smile: :smile: :smile:
 #103164  by tigerstrat
 Sat Sep 10, 2011 8:41 am
mkaufman wrote:So I can run (2) 2x12's, each with (2) 8-ohm speakers wired in parallel.
each cab will be rated at 4 ohm....if you connect a 4 ohm load to each of your two speaker jacks, the amp will do the math and see a 2 ohm load. probably safe for most BF/SF Twins, but the jacks are parallel, they are not "4 ohm each", the amp sees every load that gets connected
 #103165  by hippieguy1954
 Sat Sep 10, 2011 9:30 am
tigerstrat wrote:
mkaufman wrote:So I can run (2) 2x12's, each with (2) 8-ohm speakers wired in parallel.
each cab will be rated at 4 ohm....if you connect a 4 ohm load to each of your two speaker jacks, the amp will do the math and see a 2 ohm load. probably safe for most BF/SF Twins, but the jacks are parallel, they are not "4 ohm each", the amp sees every load that gets connected
That is not true, mkaufman. It distinctly says on the back of my twin: 4 ohms for speaker out put and 4 ohms for extension speaker out put. It is designed to have two separate 4 ohm out puts. It also says that in the Fender Manual and I have also measured the impedence to confirm.
:smile: :smile: :smile:
 #103172  by waldo041
 Sat Sep 10, 2011 10:37 am
hippieguy1954 wrote:
tigerstrat wrote:
mkaufman wrote:So I can run (2) 2x12's, each with (2) 8-ohm speakers wired in parallel.
each cab will be rated at 4 ohm....if you connect a 4 ohm load to each of your two speaker jacks, the amp will do the math and see a 2 ohm load. probably safe for most BF/SF Twins, but the jacks are parallel, they are not "4 ohm each", the amp sees every load that gets connected
That is not true, mkaufman. It distinctly says on the back of my twin: 4 ohms for speaker out put and 4 ohms for extension speaker out put. It is designed to have two separate 4 ohm out puts. It also says that in the Fender Manual and I have also measured the impedence to confirm.
:smile: :smile: :smile:
actually TS is spot on, the amp can obviously handle the 2 ohm load because that is what it will get if you throw 2 - 4 ohm cabs into it. the speaker jacks are wired in parallel internally and the output transformer will definately see this as a 2 ohm load.

peace,
waldo
 #103174  by hippieguy1954
 Sat Sep 10, 2011 11:48 am
I spoke to Fender about this a few years ago, and they told me they are both 4 ohm out puts. Even if they are wrong, the Twin is designed to handle the two 4 ohm cabs.
:smile: :smile: :smile:
 #103175  by strumminsix
 Sat Sep 10, 2011 11:53 am
I'm with TS & Waldo on this. I had my DSR opened up at my tech's and he showed me that the the 2nd jack was parallel and no add'l tap was coming off the OT.

I've done many shows running it down to 2.6 ohms. Would go any lower.
 #103498  by hippieguy1954
 Fri Sep 16, 2011 4:19 am
I've looked into this more and after some research and speaking to Fender, I found out the bottom line. I was under the impression that all twins were the same in respect to the speaker and extention speaker jacks. I was wrong. The only twins that are true 4 ohms for both out puts are the 135 watt ultra linear twins with the master volume. They are also the only twins with a direct line out. Sorry for the confusion.
:smile: :smile: :smile:
 #106876  by TI4-1009
 Wed Dec 21, 2011 8:49 am
One of the clearest resources I've found for wiring and cab hookups are the Mesa Boogie User Manuals. Near the end they show diagrams of just about every combination you can think of. Try the Lonestar, that's the one I have.

http://www.mesaboogie.com/manuals/user_ ... tml#gpm1_2